The emergence and progression of various cancers is heavily influenced by extracellular cues such as growth factors and inflammatory cytokines. The intracellular signaling pathways activated by these cues often have altered behavior and new dynamic properties, leading to neoplastic behavior. Furthermore, in a given cell, multiple signaling pathways may be activated leading to complex interactions known as 'cross-talk' and making it difficult to identify key carcinogenic pathways, or to propose targeted treatment. Therefore, a comprehensive, systems-wide view of cancer signaling is required. [unreadable] [unreadable] An important barrier to achieving a truly systemic analysis of dynamic signaling behavior in cancer cells is the lack of a tool to systematically, efficiently, and reproducibly measure the immediate signaling outputs. Here we propose to develop and enhance novel microfluidic devices that can overcome this barrier. The devices contain dozens of miniature chambers which can be filled with cells. Cells in each chamber can be independently stimulated and monitored for a distinct signaling event using conventional immunocytochemistry methods. In addition to the large number of parallel measurements that can be made in a single device, microfluidics offers precise control over experimental conditions, enhancing reproducibility and making quantification more accurate. Our existing prototypes have been tested for all major required functions and provide proof-of-principle of our technological approach. [unreadable] [unreadable] We propose to further develop the existing prototypes to enable very high-throughput experiments cataloging cell signaling signatures in diverse cancer cells. The main focus of this application is to increase the size and capacity of the device and supporting equipment, and demonstrate its functionality through a pilot screen of signaling in cancer cell lines and cells from malignant melanoma biopsies. These pilot screens may reveal new signal transduction-based markers for cancer diagnosis and suggest optimal chemotherapeutic targets. We anticipate that the device will become a powerful research tool to study signal transduction. Furthermore, the use of the device could potentially translate to clinical laboratories, specifically in its ability to perform multiple experiments directly on a patient's cells. We envision clinicians will eventually be able to use the device in personalized therapy, for example, by using a small biopsy to screen for various signaling features that mark drug susceptibility or by directly testing the efficacy of chemotherapeutic agents. [unreadable] [unreadable] [unreadable]